Steam-boiler furnace.



QW. G. MUNSON. STEAM BoILER'FUBNAcE. APPLIOATIONPILED MAY 25, 190B.

Patented'Aug. 24, 1909.

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W. G. MUNSON. STEAM BOILER PUBNACB. APPLICATION FILED MAY 25, 1908.

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Patented Aug. 24.1909.

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PatentedAug. 24, 1909.

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W. G. MUNSON. STEAM BOLER FUENAGE.

APPLoAToN FILED MAY 25, 190e.

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' To all whom it may concern:

lVIarion and State of Indiana, have invented certain new and usefulimprovements in Stea1n-Boiler Furnaces; and l do hereby declare thefollowing to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to. which it appertains tomake and use the same.

, My invention Vrelates to furnaces for steam boilers and has particularapplication to certain improvements in furnaces for feeding air andreturning smoke' and gas by the same air feeding force for promotingcombustion g and the invention consists lin the construction,combination, mode of operation, and arrangement of parts set forth inand fall'- ing Within the'scope of the appended claims.

The objecto my invention is to promote the combustion of the tire-bed,Jrevent the clinkerin and crusting thereof, and supply thereto aundanceo f artificial fuel to produce tliebest results from the heat in theproduction of steam, with complete control of the furnace, and inpreventing the Waste of fuel. v

In the accompanying drawings l have illustrated one embodiment of theinvention and in Which- Figure l shows in eleva-tion a steam boiler andits setting embodying my invent-ion, the smoke-stack in partial sectionto expose the device by which lthe product-s or" combustionare'collected therein and delivered therefrom into-the ash-pit. Fig. 2shows iu sectional elevation a steam boiler and its settingI embodyingmy invention, in feeding' air above, and the products of combustionbelow the Lgrate for promoting combustion by the same air supply force.Fig'. 3 .is a horizontal section of the same taken through theiteededoor and showing` a grated and a non-g ated coinbustion chamber,divided air conc. `i

es in the Walls surroundingi these chambers. air periorations in thesurrmindingl Walls of the latter above the grate, and air injectornozzles entering the conduits: Fie". l is an elevation of the rear endof the iurnace showing` the pipes for feeding air and the smoke andgases for promoting combustion.' Fig. 5 shows in enlarged verticalsection a portion oi' the smoke-stack and a plurality of .cones-arranged across the smoke-stack, whereby air under pressure is causedto be mixed Specification of Letters Patent. ,fr @Lent-@ii Aug. Lil.

Application filed. May 25, 1958. Serial No. sensei.

with the escaping products of combustion Within the smokeestack andexpelling the mixture into the ash-pit. Fig. 6 is a View in 'perspectiveof the interior Wall of one side of the bridge and a portion of' theconnecting' side Walls of the combustion chamber and the ash-pit showingthe Wall air receiving conduits the perforations in said Walls and airdelecting lips overhanging the said perforations :for preventing the airjets from passing` upward over the Walls into the combustion zone. Fig.'T shows in vertical'section a. detail of the conduit through which theproducts of combustion mixed with air under pressure are both forced anddrawn from the smoke-stack vand injected into the ash-pit, and the steamheating coil` in said conduit. Fig. 8 represents in sectional elelvation a steam boiler and its setting as a complete structure embodying'my invention including an air compressor and an air` storagetanl whichnecessary elements in carrying out my invention for supplying air underproper torce and volume to the airt'eeonig smoke returning devices.

The boiler l is si two combustioii -cha ibeia one il, of which bersoccupy the boiler and are ab plane. The grr beneath the front end o theboiler and has the usual feed-floor 5, and the ash-pit 6;l while the noied chamber terminates in the arched up nace. The rl .nbers are dividedby a bridge-Wall o t at Vthe products of conihustion Afrom the gratedchamber oi er the lnldg'rall and over and into the ungrated cnber intowhich they are mixed with h'k/ .-.f heated expanded air and from thencehie llame produced thereby passes into and through the arched uptakeinto and through the boiler-nues, into the usual smoke boit and into thesmoke-starli- -Ui ii divided conduit for oir rm-dercompresitire spacebeneath the on the same horizontal d combustion chamber is which itpasses into the expansion division from whichy it passes into thecombustion cion in scplled SPaCQS is?.

ed upon Walls over e 7 at the rear of the fun will presently state.

l ing both sides of the bridge-wall and the intersecting end conduits13--1/t, so that the air in the conduits will be caused to passtherefrom in a highly heated condition by means which I shall presentlyexplain, into '#15 the combustion chambers and thereby pro- Amote andmaintain a high heat beneath the `boiler. The perforations arepreferably madea quite close together' and may be so formed as to causethe air jets to be delivered at opposite or divergent angleshorizontally into the combustion chambers to give an even distributionand, as a result, a more uniform combustion. For this purpose I may makeV shaped perforations aly ternating with perforations at right angles tothe chamber walls with the branches of the V opening into the chambersso that the air jetswill be caused to mix with the bodyf of the fire onthe grate. An' important feav ture in connection with these perforationsis the `forming ofyrecesses 15, in the inner walls of the combustionchambers and on both sides of the bridge-Wall the recesses terminatingat their upper ends in deflecting lips 16 which overhang the upper rowof the perforations and thereby cause the air jets therefrom to bedeflected downward and prevent them from being drawn up and along thevertical walls of the combustion 40 chambers the air-jets thereby beingpractically confined 'to the iire-bed.

It will be noted referring to Fig. 3 that the air'conduit is dividedcentrally of its width 'by a partition 17, which extends nearly thelength of the walls of the combustion chambers, the function of whichpartition is to divide the conduit into a space 18 next to the outerside wall, into which air under pressure is injected, and acorr/.iranieating space 19 next to the chamber walls into which theinjected air is expanded before it passes through the perforations intothe combustion chambers. The partitions are separated or interruptedat'the bridge -5.5 conduit, so that the air will pass from the outerspace 18, through the space 20, between the ends of the partitions, intothe inner expansion spacesl 19, formed by the Apartitions, into thecross conduit 21, of the I30 `bridge and into the end cross conduitslf3-14.

Removable partitions 27 connect the rear ends of the partitions to therear Tall, so that the 4air under pressure entering the conduitsattheir. ends will be caused to pass along the outer sides of thesepartitions and caisse by ba'ck pres' 1re return in the spaces 19, and

into the cross` spaces, so,that in use the outer 'conduit spaces arealways filled with air under pressure; while the inner spacesvare filledwith air under less force and which it will be understood, is constantlysupplied fro'm the outer spaces into which the air is received frol n-asource of supply under pressure. i v

The provision for supplying the wall conduits with air under pressureconsists, in the construction shown, of a branch-pipe 28 connecting asupply-pipe 29 referably at a point betweenrithe source of) the air suply and the smoleestack, 'and extendin rom such connection to the rearof the rnace,

has a dupreorv4 aralnch each branch 30 termihating in anozzle 31 which,piercingpreferably the rear fornace wall, extends within each conduitspace 18 between its uter wall and the partition so that the nozzleterminates in lapping relation to the latter, and

thereby injects the zur under pressure into the outer conduit spacesfrom which it is expanded into the inner conduit space and thence intothe combustion chambers.` For this purpose the branch-pipe 28 referablyenters the wall of the main supp y-pipe 29, the air Afrom which isdetiected into the branch pipes by hoods 32 which are placed over theentrance to said branch pipes and extend into the main supply-pipe. Asadjuvant to the air supplied by these nozzles I provide the branch-pipe28, with a branch*- pipe 33, which enters the Wall of said pipe 28, andis bifurcated so that its partsl 34-34 straddle the boiler as in Fig. 4,and, passing down through the side walls, terminate in injecting nozzles35 in the outer spaces 18 of the wall conduits that is, between theirouter Walls and .the partitions, on each side of and about mediately ofthe len h of theV grated combustion chamber. similar branch-bifurcated.p1pe 33, is provided for the non-grated combustion chamber and is shownin Fig. 2'as connecting the branch pipe 28, and straddling the boiler,its branches 3-l-34t passing down through the side walls and terminatein injectin nozzles 35, in the outer spaces 18, of thewa conduits oneach side of and about mediately ofthe length'- of the non-gratedcombustionchamber.

Each brunch of the bifurcated pipes is provided with a cut off cock 50and it will be force to supply the tire-bed. The advantage .120understood, thaty all 'the'air pipes may be .used together or controlledas may be de-.

'perforations mixing with the smoke and gases from the fire-bed,produces flame of intense'heat which passes directly into the boilerfines.

In the event of the air compressor becoming disabled from any cause Iiprovide 'an emergency means whereby aii under atmospheric pressure maytireV supplied to the conduits and referring te Figs` 1 3 and 4 thisconstruction is scenes consisting ofthe' doors 11, at the end walls ofthefurna'ce which, when opened, supply air to the conduits at bothends., 'Registers 37 which" open at the side Walls and which lead toducts 38, therein down to and open into the outer conduits,` alsoprovide for the inflow of air therein, there being for this purposepreferably a pairy of such registers and ducts provided for each side ofeach combustion-chamber. YVhen .the furnace is operating under a forceddraft these doors and registers are closed.

rlhe bridge Wall is provided with passages 51, leading from the crossair conduits to a.

door 52, in the ash-pit as in Figs. 2 and 6' 'wherein it will be seenthat the bridge Wall is hollow, and that the partition therein issupported upon blocks 53.

The feed door! and the ashpit door, and

the clean out doors, are closely fitted and closed at all times when thefurnace is Working With a forced draft, .and when so working thepartitions 27 crossing the ends of the rear end cross conduits areremoved.

to allow the hot. air from the end'conduit to come 1n Contact with andheat the injector nozzles.

To give greater efficiency to the heating.

capacity of the furnace I employ the direct draft produced by the aircompressor sup ply-'pipe in connection with a smoke and gas exhaustingdevice mounted Within and extendingv across the smoke-stack draft by`which the products of combustion passing with the draft are interceptedand collected in a zone across the smokestack, mixed therein with theforced air and delivered iiito the ash-pit, lso that one'source offorced air effects under the-'same pressure the separate and distinct:functions of supplying air to the fire-bed Vabove the grate, and of ex'-llausting the products of combustion from the smoke-stackand deliveringthem beneath the grate and this operation is eected by the followingmeans. The main air supplydevice for checking the outflow of the smokeand gases, collecting them and expelling them mixed with Athe 'expellingair succes` sively from said cones into a pipe 39 Which connects Withvthe smoke-stack and extends to and opens into the ash-pit, wherebypractically all the smoke and gases that Would pass out of thesmoke-stack are taken therefrom andforced u through the grate topromotecombustion. For this purpose a group of tubular sections 40preferably of conical form are arranged in lapping relation to eachother with the flaring. ends of each opening into the smoke-stack andtheir smaller ends opening into the flaring ends, so that the smoke andgases are, by the entraining action of the air caused to be suckedsimultaneously into theflaring end of each cone, by the force 'of\`thejair passing through a central condiiit'coniposed ofitubular lappingsections 41 and connected in such manner as to cause each cone to form asuction zone in the draft space, the effect of which. is to cause thesmoke and gases to be drawn Within the cones and mixed with and ejectedtherefrom by the force of the incoming air. -T he initial cone, lapswithin the stack Vivith the end of the air supply-pipe; Awhile theterminal cone, laps Within a mixing hood 42 projecting from and securedto the outer Wall of the smoke-stack. The sections forming the centralconduit lap with each other preferably' at the lapping ends of the conesso that annular spaces 43 are formed between the lapping ends of saidcentral sections and open into the flaring ends of the cones. Preferablythe cones decrease in diameter from the intake tov the exit conc, andthe central con-` duit sections are correspondingly decreased and thisconstruction has the effect of giving the device the function of anejector, the action of which causes the air which is forced through thecentral conduit and through each cone to draw the smoke and gases fromthe smoke-stack into the flaring end of each` cone in the direction ofthe air flow and into y-,smoke and some of the gases from the smokestackinto the' mixing-hood. A pipe 39 connects this mixing-hood and, passingdown through the side Wall opens at 45, into the ash-p1t and deliverstherein the mixture of smoke, gases and air. To give'such delivery theforce of an injector a branch-pipe 46 is connected With the main airsupply-pipe between the source of the air supply and the smoke-stack,and passing down and into'the side Wall enters the wall of' the pipe 39,which leads from the mixing-hood and terminates a suitable distanceabove its outlet. In this action of the central sectional conduit andseparate 4cones the smoke and gases are taken from the smoke-stag k andmixed With air in the hood into Whi l the central air conduitterminates.

The exhausting device is kept firmly in line and supported at its inletend upon the end of the air supply-pipe by strips 48, andat its exit endthe device is supported Within the mixing-hood by strips 49, the groupof cones being connected and supported upon each other and upon thecentral sections by like strips; While the central conduit sections aresupported in separated relation at their lapping ends by like strips sothat the air has free passage through the central conduit' sections,through the spaces 43, between'their lapping 'ends and through the coneskeeping al-l the passages clear and causing each cone of the group toform an individual ejector Within the smoke-stack; While the group as anentirety forms a partial vacuum across the smoke-stack. The number ofthe cones may be varied to suit the diameter of the smoke-stack but ofWhatever number and form, their arrangement must be such as to cause aplurality of transverse drafts inl will have transverse openings incommun1- cation with the stack draft space, while the inner group ofsections Will form an air conduit and have transverse openings incommunication With the outer sections.

Coperating with the external mixinghood which opens into the smoke-stacka supplemental hood 54, is fixed to the inner Wall ot' the latter inoverhanging relation to the upper edge of the external hood so as toarrest and cause the deflection of the products of combustion Whichmightpass4 the vacuum producing' device, into the external hood. As a meansof causing the arrest ot the `stack-dra ft the flaring 'end of eachouter section ofv the partial-vacuum rroduciiig device is projectedtoward the in etl end-or' the compressed air supply-pipe so that at itsupper` edge each section will overhan its lower edge and thus assist thesuction unction of the central conduct and increasetlie exhaustinglcapacity of the device. lin the mixing' function of the hood it is alsocaused to produce a partial vacuum at the receiving end of thesmoke-pipe and to cause the extension ot this partial vacuum into thesmoke-pipe I provide it near the outlet of said hood with a contractedneck 55 of ccnical form and having the function of a nozzle andproducing thereby a more acute artial vacuum at the entrance of thesmoke-pipe.

It is important that the mixture ejected from the smoke-stack be ashighly heated as possible before it is delivered into the ash-pit, andfor this purpose l utilize steam preferably taken from the boiler domeby a pipe 56 Fig. 2 leading to and entering the Wall of the smoke-pipe39, and connected Within said pipe to a coil 57 which surrounds thereinthe air-branh-pipe 46, and passes out of said pipe 39, into theash-pit.,

This steam coil heats the air passing from the compressor to thesmoke-stack and to the ejector pipe 46; while the delivery of the steamWithinthe ash-pit serves to further heat the mixture therein and toagitate and eiect its complete mixturelbefore it passes up through thegrate into the lire-bed, as the steam will leave the coil under pressureand spread beneath the grate, and the ashpit being air-tight, themixture fed to the re therefrom will be smoke, gas, air and steamj1 thesteam pipe for that purpose having a regulating valve 58, Fig. 8. lllhesteam coil does not contact with the inner WallsA of the smoke-pipe andis of a size to give free passage therein to the products of combustion.

-I find in practice that the ordinary blower used as an air-compressorWill not produce the required air pressure for the stacksmoke exhausterand for all the air and smoke-pipes, or a uniform pressure in all thepipes and particularly in the conduit in jecto. s and to overcome thisobjection It supplement the air-compressor with an\ air storagetank 59located between the air-'cbmpressor 60 and the smoke-'stack which tactonly provides for the required pressure, and volume but serves as themeans b which such pressure maybe made fr pre ominate' over the air andsn1okepipes by the pro- 25' these are. referm vision of a regulatinggate S2 in the pipe 29, which connects the storage-tank with theexhausting device kof the smoke-stack. The pressure in the storage-tankis indi ,ated by 5 agage 63. To obtain the full advantage in the use ofthe storage-tank provision is made by a coiled pipe tether-ein havingconnection (not shown) with the steam space of the boiler, for heatingby radiation from the coil, the air stored in the tankso that the airthat supplies all the pipes is rst heated in the storage-tank, then .inthe smoke-stack exhausting device, then in the sinoke-pipe lead ing tothe ashpit, then the ash-pit, then v by the heated ivalls of theconduits Whicn surround the combustion-chambers, and in this 'Way theforce of the air is reduced before its eri'snce inte the fire-bed, thesupply .in ash-pit being always stronger than that delivered into thecombustion chambers, and

cross conduit and return under less force in the other side 'of thesaine conduit and be caused to be highly heated in its course and to-befed through the perforations into the combustion-chambers; that the airfrom these horizontal injectors is under greater .pressure than the airfrom the vertical injectors and therefore the return dow of the air inthe conduits is not interfered with; that the feeding of an in this waywill 40-A produc'e an a proximately white heat in the combustion-ciambers; that 'the several air and smoke-pipes are provided with controllin cocks 50, by which' f iill control may be i hadY of the pressureand,r supply; that the branch-pipe etti, serving/as an air injector'forthe smoke and gases'is heated in the pipe 39, by which they areconducted to and delivered'into the aslrpit; that this injector airbranch-pipe Aaids 1n produc-ino' a partial vacuum in the smokedelivering pipe and also assists in foianing a stronger partial vacuumin the exhausting cones; that the vair, smoke andv gases, are mixed inthe hood v of the exhausting device practically Within the 'smoke-stackand again mixed in the delivcrin j pire by the branch-pipe 46, and thatt is branch-pipe prevents any back ressure of the mixture; that from theforced draft and mode of promoting coinbustion, the smoke-'stack neednot iextend more than fifteen feet out of lthe rodf of a buildin thatthe controlling cock 'in the smoke delivering pipe serves to out ofi"any back draft through to the smoke stack in 'ease the air-compressor orengine may be out of uorkiiig condition; that by the provision of thecontrolling cocks, air at atmospheric pressure may be supplied to theWall con-- duit-s through the end doors thereof, ,which also affordaccess for cleaning out the conduits; that in such case the smokeexhausting device is rendered inoperative While the my improvement l donot Wish to be limited to the precise details herein set forth',inasmuch as minor changes in the form, proportion, and exact manner ofassembling of the parts may be made Without departing from the spirit ofthe invention. Nor do l Wish to be confined to the use of the duplexcoinbustion chambers as some of the features of my invention could beused with the grated combustion chamber only.

lt is important to note that the force and capacity of the exhauster beeffectively maintained to insure the most complete exhaustion of thesmoke and gases from the smoke-stack and for this purpose the exhaustingdevice is rendered functional by the joint action of three forces whichtogether insure the effectiveness of the exhausting device in divertingsubstantially all the smoke and gases from thesinoke-stack. For thispurpose the injector in the receiving end of the smoke-pipe coperatesWith the injector in the delivering end of said pipe, the tivo ejectorsacting with a suction force upon the delivering end of the exhauster andthe storage-tank acting with a driving force in the same direction uponthe receiving end of the exhauster.

fxcept for the purposes of the combination of devices herein set forthin the claims, l do not in the Letters PatentV to bc issued on thisapplication' claimreturning smoke for promoting combustion by means ofan exhausting device comprising a plurality ofV hollow cones mounted inthe Walls of the smoke-stack across the draft-space and an air conduitof lapping sections extending centrali throuGh the cones the cones and.Y Y a; 7

` and leading to the ash-pit, asthe said invention constitutes thesubject .matter of claims in a divisional application filed by me onDecember 1., 1908 under Serial Number 465,54for improvements in smokeand gas consuming furnace; nor do-I claim herein the features ofconstruction whereby the function of the storage-tank is reinforced byan ejector Within the receiving end of the smoke-pipe and an ejectorWithin the delivering end of the said pipe.

i claim-' 1. The combination in a steam -boiler furnace, a grated and anon grated combustion-chamber, a bridge-Wall dividing thecombustion-chambers, the Walls surrounding and forming the combustionchambers having conduits which are divided longitudinally into separatecommunicating passages, and the said chamber Walls having perforationsopening into the inner assagesbf said conduits and into said cham ers,and means for forcing air into a division of the conduits.

2.' The combination furnace, a grated and a non-gratedcombustion-chamber, a bridge-Wall dividing the combustion-chambers, theWalls surrounding the combustion-chambers and the bridge- Wall providedWith .separate parallel communicating conduits or passages, one of saidpassages having perforations, opening into said chambers at their'sides,ends, and at' both sides of the bridge-wall, and means for forcing airinto the other passage of the conduit from which it enters into thecombustion-chamber.

. 3. The combination in a steam-boiler furnace, a grated and anon-grated combustion-chamber, a bridge-wall dividing said chambers, theWalls surrounding said chambers provided With communicatlng conduitshaving perforations opening into said chambers, the side conduits beingdivided longitudinally into communicating spaces, a pipe leading from asource of vcompressed air supply and having connections extending to,entering and `terminating in an injecting nozzle Within a division ofeach conduit at one end of the furnace, and cocks in Asaid pipeconnections for controlling the volume and regulating the force of theair injected into said divided conduits.

in a steam boiler under com ression injected into the conduits on" onesi e of their dividing partitions is in an injecting nozzle Wit inaidivision of said conduits at one end of the furnace, a branch-pipehaving communication With sai( air supply-pipe and extending down oneacl -side of the boiler,'terminating in a noz le Within the conduits-at each side of the vcombustion-chamber, and cocks in vsaid pipeconnections for controlling the-volume and re lating the force of theair injected into sald conduits.

6. In a steam-boiler furnace, a grated and Va non grated combustionchamber, the walls surroundinr said chambers provided with longitudinaly divided communicating conduits .having perforations opening into saidchambers, a pipe leading from a source f compressed air supply and pipeconnections therefor extending to, entering and terminating in anIinjecting nozzle Within adivision of said conduits at/one end of thefurnace, independent inea/ns for sup lying air from the main supply-pipeto an Within adivision of/the conduits at each side of thecombustion-chamber, and cocks in said pipe connections for controllingthe volume and regulating the force of the air injected into saidconduits.

7. In a steam-boiler furnace, a grated comlmstion-chamber, the Wallssurrounding saidy chamber and the bridge-Wall having air conduits andperforations opening into said chamber, partitions dividingleach conduitinto communicating spaces into lone of which the Wall perforations open,an air injecting `pipe terminating in an injecting nozzle within eachconduit between the partition and the outcr Wall of the furnace, andmeans for feeding air under pressure to said nozzles.

S. ln a steam-boiler furnace, a ated combustion chamber the side Wal sforming which provided with conduits and having perforations openinginto said chamber, par: ttions dividing each conduit into commu-I.nicating passages into one of which theshid perforations open, the saidpartitions each having a removable section at the inlet end of eachconduit, anjair'injecting pipe ter- .minating in a nozzle Withintheend'of ,the outer passage, and means for eeding air to said nozzles.

9j The combination in a steam-boiler furlcombustionrhamber the Wallsouter Walls surrounding which are divided longitudinally into separatecommunicating passages, 'and the said chamber Wallshaving perforationsopening into the innerof the divided passages, means for injecting airhorizontally into one end of each of said inner passages, and means forinjecting air under pressure ver" cally into the same passages.

a non-grated combustion-chamber the outer side walls forminnr whichprovided with conduits extending iorizontally the length of saidchambers and having perforations Iopening horizontally into saidchambers, a bridgei wall dividing said chambers and having a passagethrough it in communicationv with said side wall conduits, the oppositesides ot' the bridge-wall having perforations open ing into saidchambers, the said chambers and bridge-wall having recesses into whichsaid perorations open, and an imperforate lip continuous around andoverhanging said perforations with a downward defiecting under wall,Aand means ior feeding air into said conduits.

l1. In a steam-boiler furnace, agrated and a non-gratedcombustion-chamber the walls forming which and the bridge-Wall havingair conduits extending to and opening at each end of the furnace walls,a. door closing each end opening, the said conduit `Walls including thebridge-wall having perforations opening into the chambers on a planeabove the grate, and registers in the vertical walls on each side of theboiler, each register having an air-duct extending to and terminatingWithin the conduits, said registers be-- ing on each side of eachcoinbustion-chamber.

i2. In a steam-boiler furnace, a grated combustionchaniber the wallsforming which having' conduits side by side each having freeconnnunication, that conduit which is next to the chamber havingperforations opening' therein, the two outside conduits each -opening atthe end walls, and doors closing such openings, whereby air underatmospheric pressure may be admitted through said'end openings into saidconduits heated and passed through said perforations into thecombustion-chamber.

13. In a steam-boiler furnace, a grated forming which having conduitsside by side each having free communication, that conduit Wall which isnext to the chamber having perforations opening into said chamber, aninjectornozzle entering the end wall4 of each of the outs side conduits,and means for supplyin air under compression to said in'ectors', w erebythe outer conduitreceives he compressed air and freely supplies it tothe inner conduit which thereby is causedA to have the lO. In asteam-boiler furnace, a grated and' function of an expansion-chamberfrom which the air is supplied to the combustionchamber for the purposestated.

14. In a steam-boiler furnace and in combination, a grated and anon-grated cornbustion-chamber the Walls forming which having conduitsside by side in free coinmunicat-ion with each other and the ,Wall ofthe inner conduitl having perforation-'s opening into said'chambers, aninjector'fnozzle entering the non-perforated outer conduit, branch-pipesterminating each Within said outer conduit, and stop cocks in saidpipes, whereby the air supplied by the injectors is under greaterpressure than the air supplied by the branch pipes to said.` conduits,substantially as described.

l5. In a steam-boiler furnace and in combination, a grated and a nongrated coinbustion-chaniber the walls forming which having conduits sideby side in free com- 'munication with each other, the Wall of the innerconduit having perforations opening into said chambers, an ejectornozzle enter-` ing the end iv'al'l of'each outside conduit, airsupplying pipe connections for each injector nozzle, branch pipesconnecting said air supply pipe one for each combustion-chamber andterminating each within the said outer conduit, said pipes and injectorssupplying airV under pressure to said conduits, a smoke and gasexhausting-device Within the smokestack, an air compressor, and astorage-tank connecting the exhaust-device With the stor' age-tank, apipe connecting the exhaustfde vice with the ash-pit of thecombustionchainber, and stop-cocks in said pipes Whereby the airsupplied by the branch-pipes to said conduits by the injectors is undergreater pressure than the air supplied by the branchpipes to saidconduits substantially as described for the purpose specified.

16. I n a steam-boiler furnace, 'a combusf tion-chamber, the ash-pit,and a smolrc-staclr, a smoke and gas exhaustingdeviceacross thesmoke-stack, an air supply-pipe connecting 4 the stack with theexhausting device, an airstorage tank connected to the air supplypipe,an air-compressor connected to the storage-tank, a pair of injectors incommunicavtion with the combustion-chamber and with iis the supply-pipe,a pipe connecting the injectors with the supply pipe, and a pipe connecting the exhausting device With the ashpit, whereby the air supplyforce for the exhausting device, the combustion-chamber and the ashit isprovided by the saine vol-` ume and un er the same pressure.,

17. In la stea1n-boiler furnace, the following'instrumentalities, acombustion-chamber, the ash-pit and the smoke-stack, a smoke and gas'exhausting, device across the smokest-ack, an air supply-pipe connectingthe stack with the exhausting device, means for supplying air undercompression to -said pipe, a pair of injectors, means for connecting theinjectors With the combustion-charnhei', a pipe connecting the injectorswith the air supply-pipe, und n pipe connecting the exhausting devicewith the ash-pit, the said injector connecing pipes being connected tothe nir-supi'iiying-pipe in advance of its connections with theexhausting device, whereby the feeding of (he air to the injectors andto the exhausting device is effected from/then@ same nir supply underthe same pressure.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing Witnesses.

WILLAM GURLEY MUNSON.

Vitnesses CHARLES R. Yoim CECILIA A. BEACH.

